The invention relates to a sheet-metal cage for a rolling bearing.
Like all cages used in rolling bearings, the sheet-metal cage has the tasks of guiding the rolling elements and of keeping the rolling elements at a distance from one another. To also achieve a high basic load rating of the rolling bearing, as many of the rolling elements as possible should be accommodated in the rolling bearing. A large reference circle of the cage makes it possible to minimize the distance between the rolling elements, since the cage cross-piece lies outside the center of the rolling elements. To make it possible in this design, for example in a cylindrical roller bearing, for the rolling elements to still be held, e.g., against falling out during bearing assembly, plastic retaining clips are additionally used. The plastic retaining clips just have the task of holding the rolling elements during assembly of the rolling bearing. During operation of the rolling bearing, the rolling elements are guided only by the sheet-metal cage.
Such a cage is shown in DE-U 7034682. The disadvantage of this solution is that additional retaining clips are used, which have to be fitted individually after producing the cage. A further disadvantage of this arrangement is that the snap-in connection of the retaining clips does not represent a secure connection in all operating states of the rolling bearing. The retaining clips may fall out of the cage during operation.
DE 1805265 C3 shows a cage which is produced by being punched out from a sheet-metal strip combined with bending the ends around and welding the ends together.
In this cage design, it is not possible to position the reference circle outside the center of the rolling elements.
It is consequently the object of the invention when designing a sheet-metal cage to combine maximum basic bearing load rating with minimized production costs. The invention concerns a metal window cage for a rolling bearing supporting cylinder rollers. The cage has at least one ladder-shaped bent segment bent around to define the window cage. Joints are formed at adjacent cage segment ends which are interlocked in a dovetail shape lock at crosspiece regions at the segment ends. The crosspiece regions at the joints are encapsulated with a connecting element to permanently connect the segment ends.
Cylinder roller retaining clips are molded at the connecting elements at the segment ends at the joints and also at the crosspieces between neighboring cylinder rollers, and the clips project radially inwardly to prevent the rollers from leaving the cage prior to installation of the cage and rollers in a bearing.
The major advantage of the invention is that it dispenses with the xe2x80x9cweldingxe2x80x9d operation at the joint after the sheet-metal cage or sheet-metal cage segments have been bent around, and it replaces that connection by using plastic to connect the ends of the sheet-metal cage. During the encapsulation or molding in plastic, all of the retaining clips are simultaneously molded on at the connecting point and at the cross-pieces using one mold. This avoids fitting of the individual plastic retaining clips after the sheet-metal cage has been produced.
A further advantage of the cage of the invention is its positive interlocking of the joined ends of the cage at the joint with the preferred interlocking design being dovetail-shaped. The interlocking form positively absorbs the tensile and compressive stresses occurring during operation of the sheet-metal cage. As a result, the connecting element at the joint is not subjected to additional loading.